• Journal of Internet Computing and Services
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• v.11 no.2
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• pp.99-107
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• 2010

In this paper a blind watermarking algorithm for digital image is presented. The proposed method operates in wavelet domain. The watermark is decomposed into 2D-IMFs using BEMD which is the 2-dimensional extension of 1 dimensional empirical mode decomposition. The CDMA based on SS technique is applied to watermark embedding and detection process. In the watermark embedding process, each IMF of watermark is embedded into middle frequency subimages in wavelet domain, so subimages just include partial information about embedded watermark. By characteristics of BEMD, when the partial information of watermark is synthesized, the original watermark is reconstructed. The experimental results show that the proposed watermarking algorithm is imperceptible and moreover is robust against JPEG compression, common image processing distortions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.467-472
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• 2005

ECG signals are recorded for diagnostic purposes in many clinical situations. Also, In order to permit good clinical interpretation, data is needed at high resolutions and sampling rates. Therefore In this paper, we designed to compression structure using multiple wavelet basis function(SWBF) and compared to single wavelet basis function(SWBF) and discrete cosine transform(DCT). For experience objectivity, Simulation was performed using the arrhythmia data with sampling frequency 360Hz, resolution lIbit at MIT-BIH database. An estimate of performance estimate evaluate the reconstruction error. Consequently compression structure using MWBF has high performance result.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.123-130
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• 2007

It is difficult to analyse images because of multiplicative characteristics of speckle noises in SAR images. In this paper. wavelet transform is proposed for restoring SAR images corrupted by speckle noise. The multiplicative noise is transformed into a form of additive noise and then the additive noise is denoised using wavelet thresholding selections such as VisuShrink, SureShrink, BayesShrink and modified BayesShrink. Experimental results on several test images show that the modified BayesShrink yields significantly superior image quality and better Peak Signal to Noise Ratio(PSNR).

• The Journal of Information Technology
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• v.7 no.3
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• pp.113-118
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• 2004

Recently, diagnosis techniques have been investigated to detect a partial discharge associated with a dielectric material defect in a high voltage electrical apparatus. However, the properties of detection technique of PD aren't completely understood because the physical process of PD. Therefore, this paper analyzes the process on Surface Discharge of Polymer Insulator using Wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time frequency domain. As it is important to develop a non-contact method for detecting the Contamination Degree, this research analyzes the electromagnetic waves emitted from PD using Wavelet transform. This result experimentally shows the process of PD as a two-dimensional distribution in the time-frequency domain. The method is shown to be useful for detecting prediction of contamination degree.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1593-1594
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• 2013

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2051-2052
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• 2011

The structural defects of a heart often reflects the sounds that the heart produces. This paper describes heart sound analysis method using Wavelet transform and average Shannon energy. This can extract the features of heart sounds in various disease identify the heart sounds. Experimental results show that the presented method has potential application in detecting various heart diseases.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.210-214
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• 2000

This paper proposes a new wave absorber made of flexible net structures. The motivation of this research is that the wave absorbers which already invented are not effective in small wave flume. The proposed new wave absorber demonstrated its efficiency when used in small-length wave flume.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.25-30
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• 2005

경제정책과 관련하여 경제시계열을 작성하는 중요한 목적중 하나는 순환변동을 파악할 수 있는 정보를 제공하는 것이다. 그런데 월별 또는 분기별로 작성되는 경제시계열은 계절변동 및 불규칙변동으로 인해 순환변동 등 기조적 변화를 잘못 파악하기 쉽다. 경제시계열의 기조적 변화를 파악하기 위해서는 원래의 경제시계열에서 계절변동, 불규칙변동을 분해 후 제거해서 분석해야 한다. 이 논문에서는 웨이블렛(wavelet)을 이용하여 시계열을 분해하고 이를 통해 경제시계열의 순환변동 등을 구하고 분해 요소들을 따로 예측한 후 결합된 예측을 시도한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.820-822
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• 2003

웨이블릿 변환 영역에 제안한 알고리즘으로 여러 공격에 강인한 워터마크를 삽입하고 성능을 분석하였다. 영상의 저작권 보호를 위해 웨이블릿 변환영역의 LH, HL, HH의 중대역에 128비트열의 워터마크를 삽입하였다. 제안한 방법의 강인성을 실험하기 위해 명도 변화, 콘트라스트 변화, 노이즈, 가우시안 등 과 같은 영상처리를 하였다. 실험결과 화질의 열화를 최소로 하여 워터마크를 삽입하여 높은 효율을 얻었다.

• Journal of Korea Multimedia Society
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• v.20 no.10
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• pp.1655-1661
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• 2017

A high-speed directional interpolation algorithm based on the pattern of a $2{\times}2$ pixel block is proposed in this paper. The basic concept of the proposed algorithm is started from UDWT(un-decimated discrete wavelet transform), but there are no transform operations. In order to detect the direction of the edge, 4-pixel differences of two pairs in the $2{\times}2$ block are compared. The $2{\times}2$ block patterns are grouped into total 8 classes, and thereafter the directional interpolation is executed according to the type of the pattern. Since the calculation of the proposed algorithm is very simple and needs a few additions on integer data type, the computation time is almost same as that of bilinear interpolation algorithm. However, experimental results show that the output quality of the proposed one is better than those of the conventional interpolation ones in the objective quality and the computation time.